On Performance of Quantized Transceiver in Multiuser Massive MIMO Downlinks

Low-resolution digital-to-analog converters (DACs) and analog-to-digital converters (ADCs) are considered to reduce cost and power consumption in multiuser massive multiple-input multiple-output. Using the Bussgang theorem, we derive the asymptotic downlink achievable rate with respect to the resolutions of both DACs and ADCs, i.e., bDAand bAD, under the assumption of large antenna number N, and fixed user load ratio β. We characterize the rate loss caused by finite-bit-resolution converters and reveal that the quantization distortion is ignorable at low signal-to-noise ratio (SNR) even with low-resolution converters at both sides. While for maintaining the same rate loss at high SNR, it is discovered that one-more-bit DAC resolution is needed when more users are scheduled with β increased by four times. More specifically for one-bit rate loss requirement, bDAcan be set by ΓbAD+ (1/2) log β⌉ given bAD. Similar observations on ADCs are also obtained with numerical verifications.